feat: 15 targeted improvements — RAG persistence, bus failover, agent hardening, deps sync

feat(rag): docs ingestion + UI/bus enhancements (P3 continuation)

Quality improvements: Unicode chars, Token class, imports, type hints, formatting

feat: WebLLM browser agent with PeerJS mesh, HybridRAG, news signals, and easter-egg ticker

feat: federated RAG + comprehensive security fixes

fix: 0 test failures; FileService; real RagService; emergency probe; chat return

feat: implement all M01-M13, X01-X04 modules + quality gate fixes